Large-span UHPC-steel box superposed beam mechanical response analysis method

Abstract

The invention discloses a large-span UHPC-steel box superposed beam mechanical response analysis method. The method comprises the steps that the height ratio, the UHPC prestress ratio and the slip coefficient of a to-be-analyzed superposed beam are obtained; a first finite element model is constructed according to the to-be-analyzed superposed beam, and a sliding unit is arranged between the upper steel box beam and the lower UHPC beam; according to the slippage coefficient, slippage damping in all directions is given to the slippage unit, and according to the material attributes of the upper steel box beam and the lower UHPC beam, values are assigned to the corresponding units in the first finite element model; and performing mechanical response analysis on the large-span UHPC-steel box superposed beam by applying uniformly distributed loads to the top of the assigned first finite element model. According to the method, a relatively complex load redistribution process is simplified into a group of slip coefficients, so that rapid and effective mechanical response analysis can be conveniently carried out on the to-be-analyzed superposed beam in a simulation mode, and the stress characteristics of a structural system in a normal use state and an ultimate bearing capacity state are determined.

Description

Technical Field

[0001] The invention relates to intelligent design analysis technology, and in particular to a mechanical response analysis method for a large-span UHPC-steel box composite beam. Background Art

[0002] For the main bridge of the super-large bridge with a main span of more than 300m, in order to optimize the stress of the main beam and give full play to the material characteristics, according to the mechanical characteristics of the main beam, the middle support height-changing section is proposed to be a combined section of equal-height steel box beam plus variable-height UHPC, and the remaining beam sections are equal-height steel box beams. Its main feature is the structural system of upper steel box beam and lower UHPC. The structural stress is reasonable, the system type is novel, the innovation is outstanding, and it has broad application prospects.

[0003] In the current existing technology, there is still a blank in the relevant research on this structural form. Since the steel-concrete parts are combined after forming, the force mechanism is different from that of the traditional structure. Therefore, the equal-height steel box girder + variable-height UHPC laminated combined beam bridge structure presents unique characteristics, which is prominently manifested in that the bending and shear bearing capacity distribution of the structure will show more complex changes under different prestressing and structural conditions, so a technical solution that can perform rapid mechanical response analysis on the structure is needed. Summary of the invention

[0004] In order to at least overcome the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a method for mechanical response analysis of a long-span UHPC-steel box composite beam.

[0005] The present application embodiment provides a method for analyzing the mechanical response of a long-span UHPC-steel box composite beam, including:

[0006] Obtaining a height ratio and a UHPC prestress ratio of the composite beam to be analyzed, and converting the shear capacity of the shear connection member between the steel box beam and the UHPC beam in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio; the height ratio is a height ratio between the upper steel box beam and the lower UHPC beam of the composite beam to be analyzed; the UHPC prestress ratio is a ratio between the prestress adopted by the lower UHPC beam and the maximum allowable prestress;

[0007] A first finite element model is constructed according to the composite beam to be analyzed, and a sliding unit is set between the upper steel box beam and the lower UHPC beam;

[0008] Assigning sliding damping in each direction to the sliding unit according to the sliding coefficient, and assigning values ​​to corresponding units in the first finite element model according to material properties of the upper steel box beam and the lower UHPC beam;

[0009] The mechanical response analysis of the long-span UHPC-steel box composite beam was carried out by applying a uniformly distributed load to the top of the first finite element model after assignment.

[0010] When implementing the embodiment of the present application, in order to facilitate the analysis of the composite beam to be analyzed, it is necessary to select appropriate analysis data, among which the height ratio and UHPC prestress ratio are parameters that have a greater impact on load redistribution. For shear connection components, since there are many optional structures and parameters of shear connection components, and the impact of load redistribution on different shear connection components under this structure is complex, in order to facilitate analysis, it is necessary to convert the shear resistance of the shear connection component into a slip coefficient through the height ratio and UHPC prestress ratio; it should be understood that the slip coefficient in this application is an array containing damping in three directions of x, y and z, where x is the damping of the shear connection component in the horizontal lateral direction, y is the damping of the shear connection component in the horizontal longitudinal direction, and z is the vertical damping of the shear connection component. The height ratio and UHPC prestress ratio are proposed to dedimensionalize the analysis and facilitate the corresponding analysis.

[0011] In the embodiment of the present application, after obtaining the slip coefficient, the mechanical response analysis can be performed by means of finite element simulation, wherein the shear connection member is simplified into at least one layer of sliding units in the constructed first finite element model. Since the relevant sliding properties of the shear connector have been simplified into three-way sliding damping through the above analysis process, it is only necessary to assign values ​​to the corresponding units to perform the mechanical response analysis. When performing the mechanical response analysis, the required uniformly distributed load can be applied to the top of the finite element model to obtain the corresponding stress, strain, displacement and other data, which belongs to the prior art and is not limited in the embodiment of the present application. The embodiment of the present application simplifies the relatively complex load redistribution process into a set of slip coefficients through the above technical scheme, thereby facilitating the rapid and effective mechanical response analysis of the composite beam to be analyzed through simulation, thereby clarifying the stress characteristics of the structural system under normal use and ultimate bearing capacity.

[0012] In a possible implementation, converting the shear capacity of the shear connection member between the steel box girder and the UHPC girder in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio includes:

[0013] Obtaining the shear resistance parameters of the shear connection member; the shear resistance parameters include a shear resistance ratio and a buried depth of embedded parts; the shear resistance ratio is the ratio of the shear resistance stiffness of the steel structure to the shear resistance stiffness of the concrete structure in the longitudinal section of the shear connection member; the buried depth of the embedded parts is the maximum depth of the steel structure in the shear connection member into the concrete structure;

[0014] The height ratio, the UHPC prestress ratio and the shear resistance parameter are input into a preset analysis model, and the slip coefficient output by the analysis model is obtained.

[0015] In a possible implementation, the generating of the analysis model includes:

[0016] Constructing a scaled model specimen including a sample steel box girder and a sample UHPC beam, wherein the sample steel box girder is located above the sample UHPC beam, and the sample steel box girder is connected to the sample UHPC beam through a sample connecting member;

[0017] The sample height ratio, sample prestress ratio, sample shear ratio and sample buried depth of the scaled model specimen are obtained; the sample height ratio is the height ratio of the sample steel box beam and the sample UHPC beam of the scaled model specimen; the sample prestress ratio is the ratio between the prestress adopted by the sample UHPC beam of the scaled model specimen and the maximum allowable prestress; the sample shear ratio is the ratio of the shear stiffness of the steel structure in the longitudinal section of the sample connection component to the shear stiffness of the concrete structure; the sample buried depth is the maximum depth of the steel structure in the sample connection component penetrating into the concrete structure;

[0018] Applying a uniformly distributed load to the top of the scaled model specimen, and recording a deflection change curve at the bottom of the scaled model specimen and a horizontal slip curve of a sample connecting member;

[0019] Constructing a second finite element model corresponding to the scaled model specimen, and setting a sample sliding unit between the sample steel box beam and the sample UHPC beam;

[0020] Assigning initial sliding damping in three orthogonal directions to the sample sliding element, and assigning values ​​to corresponding elements in the second finite element model according to material properties of the sample steel box girder and the sample UHPC beam;

[0021] Applying the same uniformly distributed load as in the model test to the top of the second finite element model, and obtaining a sample deflection variation curve and a sample horizontal slip curve of a sample slip unit at the bottom of the second finite element model;

[0022] When at least one of the first similarity and the second similarity does not meet the preset requirements, the sliding damping of the sample sliding unit is adjusted and calculated again until both the first similarity and the second similarity meet the preset requirements; the first similarity is the similarity between the sample deflection change curve and the deflection change curve; the second similarity is the similarity between the sample horizontal sliding curve and the horizontal sliding curve;

[0023] Recording the sliding damping of the sample sliding unit in three orthogonal directions when both the first similarity and the second similarity meet the preset requirements as the sample sliding coefficient;

[0024] Conduct multiple groups of scaled model specimen tests and finite element model calculations to obtain multiple groups of sample slip coefficients, sample height ratios, sample prestress ratios, sample shear ratios, and sample burial depths;

[0025] The sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth are used as data input, and the sample slip coefficient is used as data output to train a neural network model to form the analysis model.

[0026] In a possible implementation manner, adjusting the sliding damping of the sample sliding unit includes:

[0027] Setting adjustment intervals centered on the initial slip damping for the slip damping in three orthogonal directions respectively;

[0028] During adjustment, the slip damping is randomly selected within the corresponding adjustment range, and the closer the value is to the initial slip damping, the higher the random weight is.

[0029] In a possible implementation manner, the adjustment interval is a normally distributed interval centered on the initial slip damping.

[0030] In a possible implementation, calculating the first similarity and the second similarity includes:

[0031] Calculating the cosine similarity between the sample deflection change curve and the deflection change curve as the first similarity;

[0032] The cosine similarity between the sample horizontal slip curve and the horizontal slip curve is calculated as the second similarity.

[0033] In a possible implementation, training a neural network model to form the analysis model includes:

[0034] Constructing a neural network model, wherein the input layer of the neural network model includes four input neuron nodes, one output neuron node and multiple hidden neuron nodes;

[0035] Construct the weights from the input neuron node to the hidden neuron node and the weights from the hidden neuron node to the output neuron node;

[0036] Input the sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth as data inputs into four input neuron nodes respectively, and record output data of output neuron nodes;

[0037] The difference between the output data and the sample slip coefficient is calculated through the loss function, and the weights are adjusted until the difference meets the expected requirements to complete the training.

[0038] In a possible implementation, performing mechanical response analysis on the long-span UHPC-steel box composite beam by applying a uniformly distributed load to the top of the assigned first finite element model includes:

[0039] The deformation, stress, strain and deflection of each part under uniformly distributed load are calculated through the first finite element model to complete the mechanical response analysis.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] The present invention provides a mechanical response analysis method for a large-span UHPC-steel box composite beam. Through the above technical scheme, the relatively complex load redistribution process is simplified into a set of slip coefficients, thereby facilitating a rapid and effective mechanical response analysis of the composite beam to be analyzed by simulation, thereby clarifying the stress characteristics of the structural system under normal use and ultimate bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0043] Figure 1 This is a schematic diagram of the method steps of an embodiment of the present application. DETAILED DESCRIPTION

[0044] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the embodiment of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0045] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0046] Please refer to Figure 1 , which is a flow chart of a mechanical response analysis method for a large-span UHPC-steel box composite beam provided in an embodiment of the present invention. Furthermore, the mechanical response analysis method for a large-span UHPC-steel box composite beam may specifically include the contents described in the following steps S1 to S4.

[0047] S1: Obtain the height ratio and UHPC prestress ratio of the composite beam to be analyzed, and convert the shear capacity of the shear connection member between the steel box beam and the UHPC beam in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio; the height ratio is the height ratio of the upper steel box beam and the lower UHPC beam of the composite beam to be analyzed; the UHPC prestress ratio is the ratio between the prestress adopted by the lower UHPC beam and the maximum allowable prestress;

[0048] S2: constructing a first finite element model according to the composite beam to be analyzed, and setting a sliding unit between the upper steel box beam and the lower UHPC beam;

[0049] S3: assigning sliding damping in each direction to the sliding unit according to the sliding coefficient, and assigning values ​​to corresponding units in the first finite element model according to material properties of the upper steel box beam and the lower UHPC beam;

[0050] S4: Perform mechanical response analysis on the long-span UHPC-steel box composite beam by applying a uniformly distributed load to the top of the first finite element model after the assignment.

[0051] When implementing the embodiment of the present application, in order to facilitate the analysis of the composite beam to be analyzed, it is necessary to select appropriate analysis data, among which the height ratio and UHPC prestress ratio are parameters that have a greater impact on load redistribution. For shear connection components, since there are many optional structures and parameters of shear connection components, and the impact of load redistribution on different shear connection components under this structure is complex, in order to facilitate analysis, it is necessary to convert the shear resistance of the shear connection component into a slip coefficient through the height ratio and UHPC prestress ratio; it should be understood that the slip coefficient in this application is an array containing damping in three directions of x, y and z, where x is the damping of the shear connection component in the horizontal lateral direction, y is the damping of the shear connection component in the horizontal longitudinal direction, and z is the vertical damping of the shear connection component. The height ratio and UHPC prestress ratio are proposed to dedimensionalize the analysis and facilitate the corresponding analysis.

[0052] In the embodiment of the present application, after obtaining the slip coefficient, the mechanical response analysis can be performed by means of finite element simulation, wherein the shear connection member is simplified into at least one layer of sliding units in the constructed first finite element model. Since the relevant sliding properties of the shear connector have been simplified into three-way sliding damping through the above analysis process, it is only necessary to assign values ​​to the corresponding units to perform the mechanical response analysis. When performing the mechanical response analysis, the required uniformly distributed load can be applied to the top of the finite element model to obtain the corresponding stress, strain, displacement and other data, which belongs to the prior art and is not limited in the embodiment of the present application. The embodiment of the present application simplifies the relatively complex load redistribution process into a set of slip coefficients through the above technical scheme, thereby facilitating the rapid and effective mechanical response analysis of the composite beam to be analyzed through simulation, thereby clarifying the stress characteristics of the structural system under normal use and ultimate bearing capacity.

[0053] In a possible implementation, converting the shear capacity of the shear connection member between the steel box girder and the UHPC girder in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio includes:

[0054] Obtaining the shear resistance parameters of the shear connection member; the shear resistance parameters include a shear resistance ratio and a buried depth of embedded parts; the shear resistance ratio is the ratio of the shear resistance stiffness of the steel structure to the shear resistance stiffness of the concrete structure in the longitudinal section of the shear connection member; the buried depth of the embedded parts is the maximum depth of the steel structure in the shear connection member into the concrete structure;

[0055] The height ratio, the UHPC prestress ratio and the shear resistance parameter are input into a preset analysis model, and the slip coefficient output by the analysis model is obtained.

[0056] When the embodiment of the present application is implemented, in order to achieve a simplified description of the corresponding slip of the shear connection member, in addition to the height ratio and the UHPC prestress ratio, it is necessary to obtain the shear parameters of the shear connection member itself. In the embodiment of the present application, the shear parameters used are the shear ratio and the embedded depth of the embedded parts. Since the shear ratio will affect the overall shear redistribution state and the embedded depth of the embedded parts will affect the overall shear capacity in the process of the shear connection member resisting shear slip, these two points are selected as shear parameters. For the shear ratio, in a longitudinal section of the shear connection member, the area of ​​the steel structure is calculated multiplied by the shear elastic modulus as the shear stiffness of the steel structure, and the area of ​​the concrete structure is calculated multiplied by the shear elastic modulus as the shear stiffness of the steel structure, and the ratio is calculated; and the embedded depth of the embedded parts is calculated by the maximum depth of the steel structure into the concrete structure. In order to reduce the analysis impact brought by various complex factors, the embodiment of the present application adopts a preset analysis model to perform a black box comprehensive analysis of these parameters and then obtain the slip coefficient.

[0057] In a possible implementation, the generating of the analysis model includes:

[0058] Constructing a scaled model specimen including a sample steel box girder and a sample UHPC beam, wherein the sample steel box girder is located above the sample UHPC beam, and the sample steel box girder is connected to the sample UHPC beam through a sample connecting member;

[0059] The sample height ratio, sample prestress ratio, sample shear ratio and sample buried depth of the scaled model specimen are obtained; the sample height ratio is the height ratio of the sample steel box beam and the sample UHPC beam of the scaled model specimen; the sample prestress ratio is the ratio between the prestress adopted by the sample UHPC beam of the scaled model specimen and the maximum allowable prestress; the sample shear ratio is the ratio of the shear stiffness of the steel structure in the longitudinal section of the sample connection component to the shear stiffness of the concrete structure; the sample buried depth is the maximum depth of the steel structure in the sample connection component penetrating into the concrete structure;

[0060] Applying a uniformly distributed load to the top of the scaled model specimen, and recording a deflection change curve at the bottom of the scaled model specimen and a horizontal slip curve of a sample connecting member;

[0061] Constructing a second finite element model corresponding to the scaled model specimen, and setting a sample sliding unit between the sample steel box beam and the sample UHPC beam;

[0062] Assigning initial sliding damping in three orthogonal directions to the sample sliding element, and assigning values ​​to corresponding elements in the second finite element model according to material properties of the sample steel box girder and the sample UHPC beam;

[0063] Applying the same uniformly distributed load as in the model test to the top of the second finite element model, and obtaining a sample deflection variation curve and a sample horizontal slip curve of a sample slip unit at the bottom of the second finite element model;

[0064] When at least one of the first similarity and the second similarity does not meet the preset requirements, the sliding damping of the sample sliding unit is adjusted and calculated again until both the first similarity and the second similarity meet the preset requirements; the first similarity is the similarity between the sample deflection change curve and the deflection change curve; the second similarity is the similarity between the sample horizontal sliding curve and the horizontal sliding curve;

[0065] Recording the sliding damping of the sample sliding unit in three orthogonal directions when both the first similarity and the second similarity meet the preset requirements as the sample sliding coefficient;

[0066] Conduct multiple groups of scaled model specimen tests and finite element model calculations to obtain multiple groups of sample slip coefficients, sample height ratios, sample prestress ratios, sample shear ratios, and sample burial depths;

[0067] The sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth are used as data input, and the sample slip coefficient is used as data output to train a neural network model to form the analysis model.

[0068] When the embodiment of the present application is implemented, the samples required for the analysis model training are obtained by means of scaled model tests and finite element simulation. Among them, the subsequent multiple groups of scaled model specimen tests need to be configured with scaled model specimens with different parameters such as different connectors, prestress, height, etc. to increase the richness of the samples, which can reduce the specimen preparation and specimen testing time. The preferred scale ratio is 1:20. The deflection change curve and the horizontal slip curve can be obtained by loading the scaled model specimen. In general, the deflection is measured by a dial gauge, and the horizontal slip is measured by a micrometer.

[0069] In the embodiment of the present application, in order to obtain the slip parameters corresponding to the current scaled model test, it is necessary to construct a second finite element model and perform the same uniform load loading, and then adjust the slip damping until the final calculation result matches the test result. The slip damping at this time is the sample slip coefficient corresponding to the various parameters of the current scaled model test. After multiple rounds of tests and data sampling, a large number of sample pairs can be obtained and then the analysis model can be formed through neural network model training.

[0070] In a possible implementation manner, adjusting the sliding damping of the sample sliding unit includes:

[0071] Setting adjustment intervals centered on the initial slip damping for the slip damping in three orthogonal directions respectively;

[0072] During adjustment, the slip damping is randomly selected within the corresponding adjustment range, and the closer the value is to the initial slip damping, the higher the random weight is.

[0073] In a possible implementation manner, the adjustment interval is a normally distributed interval centered on the initial slip damping.

[0074] When implementing the embodiment of the present application, in order to realize the automated process of adjusting the slip damping, it is necessary to construct an adjustment interval, wherein the adjustment interval is a data interval that satisfies the normal distribution, and the center of the interval is the initial slip damping. Randomly taking values ​​in the data interval of the normal distribution can ensure that the data offset is not too large.

[0075] In a possible implementation, calculating the first similarity and the second similarity includes:

[0076] Calculating the cosine similarity between the sample deflection change curve and the deflection change curve as the first similarity;

[0077] The cosine similarity between the sample horizontal slip curve and the horizontal slip curve is calculated as the second similarity.

[0078] In a possible implementation, training a neural network model to form the analysis model includes:

[0079] Constructing a neural network model, wherein the input layer of the neural network model includes four input neuron nodes, one output neuron node and multiple hidden neuron nodes;

[0080] Construct the weights from the input neuron node to the hidden neuron node and the weights from the hidden neuron node to the output neuron node;

[0081] Input the sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth as data inputs into four input neuron nodes respectively, and record output data of output neuron nodes;

[0082] The difference between the output data and the sample slip coefficient is calculated through the loss function, and the weights are adjusted until the difference meets the expected requirements to complete the training.

[0083] In a possible implementation, performing mechanical response analysis on the long-span UHPC-steel box composite beam by applying a uniformly distributed load to the top of the assigned first finite element model includes:

[0084] The deformation, stress, strain and deflection of each part under uniformly distributed load are calculated through the first finite element model to complete the mechanical response analysis.

[0085] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0086] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0087] The units described as separate components may or may not be physically separated. As units, it is obvious that a person of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0088] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0089] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a grid device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0090] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mechanical response analysis method for a long-span UHPC-steel box composite beam, characterized in that: include: Obtaining a height ratio and a UHPC prestress ratio of the composite beam to be analyzed, and converting the shear capacity of the shear connection member between the steel box beam and the UHPC beam in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio; the height ratio is a height ratio between the upper steel box beam and the lower UHPC beam of the composite beam to be analyzed; the UHPC prestress ratio is a ratio between the prestress adopted by the lower UHPC beam and the maximum allowable prestress; A first finite element model is constructed according to the composite beam to be analyzed, and a sliding unit is set between the upper steel box beam and the lower UHPC beam; Assigning sliding damping in each direction to the sliding unit according to the sliding coefficient, and assigning values ​​to corresponding units in the first finite element model according to material properties of the upper steel box beam and the lower UHPC beam; The mechanical response analysis of the long-span UHPC-steel box composite beam was carried out by applying a uniformly distributed load to the top of the first finite element model after assignment.

2. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 1 is characterized in that: Converting the shear capacity of the shear connection member between the steel box girder and the UHPC girder in the composite beam to be analyzed into a slip coefficient according to the height ratio and the UHPC prestress ratio includes: Obtaining the shear resistance parameters of the shear connection member; the shear resistance parameters include a shear resistance ratio and a buried depth of embedded parts; the shear resistance ratio is the ratio of the shear resistance stiffness of the steel structure to the shear resistance stiffness of the concrete structure in the longitudinal section of the shear connection member; the buried depth of the embedded parts is the maximum depth of the steel structure in the shear connection member into the concrete structure; The height ratio, the UHPC prestress ratio and the shear resistance parameter are input into a preset analysis model, and the slip coefficient output by the analysis model is obtained.

3. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 2 is characterized in that: The generation of the analysis model includes: Constructing a scaled model specimen including a sample steel box girder and a sample UHPC beam, wherein the sample steel box girder is located above the sample UHPC beam, and the sample steel box girder is connected to the sample UHPC beam through a sample connecting member; The sample height ratio, sample prestress ratio, sample shear ratio and sample buried depth of the scaled model specimen are obtained; the sample height ratio is the height ratio of the sample steel box beam and the sample UHPC beam of the scaled model specimen; the sample prestress ratio is the ratio between the prestress adopted by the sample UHPC beam of the scaled model specimen and the maximum allowable prestress; the sample shear ratio is the ratio of the shear stiffness of the steel structure in the longitudinal section of the sample connection component to the shear stiffness of the concrete structure; the sample buried depth is the maximum depth of the steel structure in the sample connection component penetrating into the concrete structure; Applying a uniformly distributed load to the top of the scaled model specimen, and recording a deflection change curve at the bottom of the scaled model specimen and a horizontal slip curve of a sample connecting member; Constructing a second finite element model corresponding to the scaled model specimen, and setting a sample sliding unit between the sample steel box beam and the sample UHPC beam; Assigning initial sliding damping in three orthogonal directions to the sample sliding element, and assigning values ​​to corresponding elements in the second finite element model according to material properties of the sample steel box girder and the sample UHPC beam; Applying the same uniformly distributed load as in the model test to the top of the second finite element model, and obtaining a sample deflection variation curve and a sample horizontal slip curve of a sample slip unit at the bottom of the second finite element model; When at least one of the first similarity and the second similarity does not meet the preset requirements, the sliding damping of the sample sliding unit is adjusted and calculated again until both the first similarity and the second similarity meet the preset requirements; the first similarity is the similarity between the sample deflection change curve and the deflection change curve; the second similarity is the similarity between the sample horizontal sliding curve and the horizontal sliding curve; Recording the sliding damping of the sample sliding unit in three orthogonal directions when both the first similarity and the second similarity meet the preset requirements as the sample sliding coefficient; Conduct multiple groups of scaled model specimen tests and finite element model calculations to obtain multiple groups of sample slip coefficients, sample height ratios, sample prestress ratios, sample shear ratios, and sample burial depths; The sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth are used as data input, and the sample slip coefficient is used as data output to train a neural network model to form the analysis model.

4. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 3 is characterized in that: Adjusting the sliding damping of the sample sliding unit includes: Setting adjustment intervals centered on the initial slip damping for the slip damping in three orthogonal directions respectively; During adjustment, the slip damping is randomly selected within the corresponding adjustment range, and the closer the value is to the initial slip damping, the higher the random weight is.

5. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 4 is characterized in that: The adjustment interval is a normally distributed interval centered on the initial slip damping.

6. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 3 is characterized in that: The calculation of the first similarity and the second similarity includes: Calculating the cosine similarity between the sample deflection change curve and the deflection change curve as the first similarity; The cosine similarity between the sample horizontal slip curve and the horizontal slip curve is calculated as the second similarity.

7. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 3, characterized in that: Training the neural network model to form the analysis model includes: Constructing a neural network model, wherein the input layer of the neural network model includes four input neuron nodes, one output neuron node and multiple hidden neuron nodes; Construct the weights from the input neuron node to the hidden neuron node and the weights from the hidden neuron node to the output neuron node; Input the sample height ratio, sample prestress ratio, sample shear ratio and sample burial depth as data inputs into four input neuron nodes respectively, and record output data of output neuron nodes; The difference between the output data and the sample slip coefficient is calculated through the loss function, and the weights are adjusted until the difference meets the expected requirements to complete the training.

8. The method for mechanical response analysis of a long-span UHPC-steel box composite beam according to claim 1, characterized in that: The mechanical response analysis of the long-span UHPC-steel box composite beam is performed by applying a uniformly distributed load to the top of the first finite element model after the assignment, including: The deformation, stress, strain and deflection of each part under uniformly distributed load are calculated through the first finite element model to complete the mechanical response analysis.

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